Journal of Oral Implantology August 2013 - (Page 425)

RESEARCH Influence of the Implant Diameter With Different Sizes of Hexagon: Analysis by 3-Dimensional Finite Element Method Eduardo Piza Pellizzer, DDS, PhD, MSc1* Fellippo Ramos Verri, DDS, PhD, MSc1 ´ Sandra Lucia Dantas de Moraes, DDS, MSc1 ´ Rosse Mary Falcon-Antenucci, DDS, MSc1 ´rgio Perri de Carvalho, DDS, PhD, MSc2 Paulo Se Pedro Yoshito Noritomi, PhD3 The aim of this study was to evaluate the stress distribution in implants of regular platforms and of wide diameter with different sizes of hexagon by the 3-dimensional finite element method. We used simulated 3-dimensional models with the aid of Solidworks 2006 and Rhinoceros 4.0 software for the design of the implant and abutment and the InVesalius software for the design of the bone. Each model represented a block of bone from the mandibular molar region with an implant 10 mm in length and different diameters. Model A was an implant 3.75 mm/regular hexagon, model B was an implant 5.00 mm/regular hexagon, and model C was an implant 5.00 mm/ expanded hexagon. A load of 200 N was applied in the axial, lateral, and oblique directions. At implant, applying the load (axial, lateral, and oblique), the 3 models presented stress concentration at the threads in the cervical and middle regions, and the stress was higher for model A. At the abutment, models A and B showed a similar stress distribution, concentrated at the cervical and middle third; model C showed the highest stresses. On the cortical bone, the stress was concentrated at the cervical region for the 3 models and was higher for model A. In the trabecular bone, the stresses were less intense and concentrated around the implant body, and were more intense for model A. Among the models of wide diameter (models B and C), model B (implant 5.00 mm/regular hexagon) was more favorable with regard to distribution of stresses. Model A (implant 3.75 mm/regular hexagon) showed the largest areas and the most intense stress, and model B (implant 5.00 mm/regular hexagon) showed a more favorable stress distribution. The highest stresses were observed in the application of lateral load. Key Words: dental implants, biomechanics, finite element analysis INTRODUCTION S ince the introduction of the Branemark system, the coronal aspect of the hexagon has gradually transformed to promote a better adaptation and an antirotational mechanism.1 The design of the original external hexagonal was designed as a gear 1 Department of Dental Materials and Prosthodontics, Aracatuba ¸ ˜ School of Dentistry, Sao Paulo State University-UNESP, Brazil. 2 Department of Surgery and Integrated Clinic, Aracatuba School ¸ ˜ of Dentistry, Sao Paulo State University-UNESP, Brazil. 3 ˜ Renato Archer Information Technology Center, Sao Paulo, Brazil. * Corresponding author, email: ed.pl@uol.com.br DOI: 10.1563/AAID-JOI-D-10-00103 mechanism and transfer of rotational torque to hold the implant during the surgical installation in the bone.2,3 The hexagon had a height of 0.7 mm to allow for adjustment during installation of the implant.2 Initially, the use of osseointegrated dental implants had been proposed only in fully edentulous patients. Gradually, that planning was expanded for partially edentulous patients and ultimately for the replacement of individual components. Prosthetic tooth implant solutions were the last to be developed by many implant systems.4,5 From that moment on, a significant number of clinical complications began to emerge.2,6 The increasing use of external hex implants Journal of Oral Implantology 425

Table of Contents for the Digital Edition of Journal of Oral Implantology August 2013

Literary Responsibility—Everyone Has a Role to Play
Rehabilitation of Surgically Relocated Integrated Dental Implants With and Without Bone Morphogenesis Protein-2
Erratum
Marginal Fit of Implant-Supported All-Ceramic Zirconia Frameworks
Influence of the Implant Diameter With Different Sizes of Hexagon: Analysis by 3-Dimensional Finite Element Method
Autologous Dental Pulp Stem Cells in Regeneration of Defect Created in Canine Periodontal Tissue
Histologic and Biomechanical Evaluation of 2 Resorbable-Blasting Media Implant Surfaces at Early Implantation Times
Efficacy of Guided Bone Regeneration Using Composite Bone Graft and Resorbable Collagen Membrane in Seibert’s Class I Ridge Defects: Radiological Evaluation
Minimal Iliac Bone Harvesting in Sinus Lift Surgery
Functional Load in Oblique Bicortical Implants: Parasinusal Implants and Palatine Implants
Ultrasonic Oscillations for Conservative Retrieval of a Rare Fracture of Implant Healing Abutment
Craniofacial Implant-Retained Auricular Prosthesis: A Case Report
Gingival Conditioning in an Implant-Supported Prosthesis: A Clinical Report
An Early Loaded Implant-Supported Mandibular Complete Arch Fixed Prosthesis in a Young Completely Edentulous Patient: A Case Report
Computer Guided Surgery for Implant Placement and Dental Rehabilitation in a Patient Undergoing Sub-Total Mandibulectomy and Microvascular Free Flap Reconstruction
Guided Bone Regeneration for Socket Preservation in Molar Extraction Sites: Histomorphometric and 3D Computerized Tomography Analysis
Osseointegration of Dental Implants and Osteonecrosis of the Jaw in Patients Treated With Bisphosphonate Therapy: A Systematic Review
Review of Current Literature

Journal of Oral Implantology August 2013